The present invention is related to a method and an apparatus for the measurement of mass or density and/or for the measurement of the humidity in a plurality of portioned units in a carrier material.
From EP 0 889 321, the entire contents is incorporated herein by reference, a microwave resonator is known which is realised as a cavity resonator in order to measure a profile of density and/or humidity on a sample in the longitudinal direction of the sample. The known microwave resonator has a cylindrical cavity, through which the sample to be measured is moved and whose changes of the resonance with respect to the empty condition permit unambiguous conclusions regarding the values of the humidity and density profiles of the sample.
From EP 1 316 630, the entire contents is incorporated herein by reference, an apparatus and a method is known for acquiring the mass and the humidity content of fibrous material in a preparatory machine for spinning works. In this, the material to be measured is guided through a cavity resonator, and the changes of the resonance properties of the microwave resonator that occur with respect to the empty condition of the resonator are recorded. Further, the speed of the material that runs through is measured.
From EP 1 467 191 B1, the entire contents is incorporated herein by reference, a method and an apparatus is known to determine the mass of portioned units of active agents, like for instance capsules, tablets and dragées. In order to sort out capsules whose mass is not within a given tolerance range at the exit of a machine for filling the capsules, it is envisioned to transport the capsules within an air flow through the microwave resonator. By way of corresponding switches or air pulses, sorting the capsules according to different masses or humidities into different containers is performed, wherein the microwave resonator measurement unit is either integrated into the machine itself, together with the throw-out mechanism, or is positioned next to the machine as an independent unit.
The present invention is based on the objective to provide a method and an apparatus for the measurement of mass or density and/or for the measurement of the humidity in a plurality of portioned units in a non-metallic carrier material which reliably measures the portioned unit independently from its carrier material by way of simple means.